Managing for old-growth conditions in second-growth temperate rainforests of South-Central Chile

Abstract

The Llancahue watershed east of Valdivia, Chile (pop. 140,000) provides a glimpse of what the native forests in south-central Chile looked like before land clearing and conversion to exotic tree plantations. Federally protected since 1929, over 500 hectares of this 1,300-hectare watershed is old growth temperate rainforest. The Universidad Austral de Chile (UACH) acquired management authority over Llancahue from the Chilean government in September 2008. UACH has goals to manage the watershed for forest products, increased water yield, wildlife habitat, and recreational opportunities. In addition to old growth conservation, they also plan to manage some secondary stands to promote old growth conditions.

The purpose of my research in Llancahue was to gain a better understanding of the native forests within its boundaries in order to develop recommendations for restoring old growth forest conditions in secondary stands. In 2007 and 2008, I measured 25 0.1-hectare plots throughout the watershed covering five forest subtypes delineated by UACH scientists using aerial photographs and GIS. I gathered data on overstory structure, understory composition, coarse woody debris, and tree growth rates and summarized it to characterize the differences between old growth and secondary forests. I then applied this data to the development of a silvicultural prescription to artificially advance forest succession within secondary stands.